Drill press attachment



March 1957 L. P. CONOVER DRILL PRESS ATTACHMENHT Filed Jan. 4, 1954 .ZORE/V P (m/ova? 3 .ammeg IL IrI DRILL PRESS ATTACHMENT Loren P. Conover, El Monte, Calif. assignor of forty-five percent to Rene Pfister, Alhambra, Calif.

Application January 4, 1954, Serial No. 401,915 7 Claims. 01. 74-421 This invention relates to an attachment for drill presses and has for its principal object to provide a drill press attachment for drilling holes of a larger diameter than the press is originally designed for.

Another object of the invention is to provide such an attachment that provides reduced speed of the drillholding shank thereof with respect to the speed of the drill spindle to which said attachment is attached. By reason of such reduced speed, a press provided with such an attachment for the tool thereof can drill larger holes and against greater cutting resistance than with directly driven tools.

A further object of the invention is to provide a speedreducing attachment for drill presses that has an aligned transmission of the thrust While drilling and which thrust is taken by the body of the attachment rather than by the speed-reducing means thereof. In this manner, said speed-reducing means is smoother in operation, has longer life, and requires less power to operate.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the follow ing description. However, the drawing merely shows and the following description merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

In the drawing, like reference characters designate similar parts in the several views.

Fig. l is a plan sectional view showing a preferred embodiment of the present attachment in operative position relative to the column of a drill press.

Fig. 2 is an enlarged partly broken elevational view of said attachment and in quarter section to show the speedreducing means therein.

Figs. 3 and 4 are cross-sectional views, to a reduced scale, taken respectively on lines 3-3 and 44 of Fig. 2.

Fig. 1 shows the present drilling attachment 5 in operative association with the column 6 of a drill press. Said attachment is provided with a radially extending arm 7 bearing against the side of said column, and a coil spring 8, connected at its ends to said arm 7, encircles the column. As shown, the column prevents counterclockwise rotation of attachment 5 and spring 8 resists clockwise rotation. Said arm 7 is arranged to engage one side or the other of column 6, depending on the direction of rotation of the drilling tool carried by the attachment which, in the present instance, is the same as the direction of rotation of the drill spindle.

The attachment 5 comprises a housing 9, an input shank 10 entering the top center of said housing, an aligned output shank 11 extending from the bottom of said housing, reducing gearing 12 operatively intercon- 2. meeting said shanks, and bearing means 13 in the center of the housing to receive the thrust of said shanks.

The housing 9 comprises a body 14 that has a central bore 15 which, at the upper end of the body, is in communication with a set of bores 16 arranged uniformly around the bore 15 as a center. Three bores 16 are shown although two or four or more may be provided, as desired. In the present construction, bore 15, at the lower end of the body 14, is counter-bored as at 17 and the same is in communication with a set of bores 18 smaller than bores 16 and aligned therewith.

Body 14 is closed at the top by a plate 19 and at the bottom by a similar plate 20, the body and plates being interfitted and maintained concentrically by means of annular shoulders 21. Each plate is provided with a central hole 22, the same being in alignment with bore 15 and counter-bore 17. Said holes 22 have respective upper and lower annular shoulders 23.

The plates 19 and 20 are secured to the body 14 as by bolts 24 that pass through said plates and engage screw seats 25 provided in said body.

The input shank 10 is of any desired shape and is adapted to enter and be altixed to the chuck of a drill press to be rotated by the spindle mounting said chuck, or adapted to enter a similarly shaped socket on the drill press or other machine to which it is attached. Integrally formed on said shank 10 is a pinion gear 26 that resides in the upper end of bore 15. A central position of said gear in said bore is maintained by a radial bearing 27 that is press-fitted in hole 22 of plate 19 and against shoulder 23 of said hole. In this manner, gear 26 is mounted to rotate in housing 9 on the axis thereof.

The output shank 11 is larger in diameter than shank 10 and is provided with a tapered "socket 28 that is adapted to receive the shank. of a drilling tool of conventional form. Said shank 11, by means of splines 29, carries a gear 30 that resides in counter-bore 17. A radial bearing 31, in hole 22 of plate 20 and similar to hearing 27, holds said shank 11 in axial alignment with shank 10.

The reducing gearing 12 includes gears 26 and 30 and further includes transmission gearing disposed in the bores 16 and 18 of the body 14. The latter comprises gears 32 in bores 16 and in mesh with pinion gear 26, and pinion gears 33 in bores 18 and in mesh with gear 30. Each gear 32 connects with a pinion gear 33 by means of splines 34 on a spindle 35 that is mounted by needle bearings 36 in the middle portion of each bore 18.

Thus, the speed of rotation of shank 11 relative to shank 10 depends on the ratios between gears 26 and 32, and 33 and 30. As shown, gears 32 are twice the diameter of pinion gear 26. Therefore, spindles 35 and pinion gears 33 thereon will revolve in the housing at half the speed of shank 10. Gear 30 is shown as twice the diameter of pinion gears 33. Therefore, gear 30 and spindle 11 rotate at one-quarter the speed of shank 10. The speed ratio between the spindle of the drill press and the tool mounted in shank 11 is, therefore, four to one in the attachment illustrated.

Since the tool carried by shank 11 has a downward force applied in the usual manner, the bearing means 13 is provided between gears 26 and 33 to absorb the resulting thrust and prevent transmission thereof to the reducing gears. Said means comprises a tapered roller bearing 37 having its outer race 38 pressed into bore 15 and its roller cage 39 carried by the end of gear 26. Thus, the thrust transmitted through shank 10 is taken by body 14 through bearing 37. Similarly, the thrust transmitted through the body is taken by shank 11 through a tapered roller bearing 46 that is similar to and in opposed relation to hearing 37.

Helical gears are preferred, as shown, for quietness of operation, and reduction of back lash, and of wear. It will be evident that the attachment may be reversed if increased output speed is desired. The transmission gears may run in a suitable lubricant introduced into the housing through 'a pressure fitting in cover plate 19 or any other suitable part of housing 9.

The above description speaks of using the present attachment on a drill press. Since the same may be mounted on a portable drill, including an electric drill, a pneumatic drill, or the like, the term drill press is intended to include all such drills.

While I have illustrated and described what I now contemplate to be the best mode of carrying out my invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention. It is, therefore, not desired to restrict the invention to the particular form of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described our invention, what we claim and desire to be secured by Letters Patent is:

1. A drill press attachment comprising a housing adapted to be mounted on the spindle of said press, means to hold said housing non-rotational, axially aligned input and output shanks extending from said housing, a thrust-receiving bearing mounted on the end of each shank and afiixed to the housing, a gear on each shank adjacent said bearing, one gear being larger than the other, a transmission gear in mesh with each gear on each shank, and a common spindle on which the transmission gears are afiixed, said spindle being mounted in a bearing carried by said housing and located in between said transmission gears.

2. A drill press attachment according to claim 1: said thrust receiving bearings being disposed in opposed relation so that one transmits the thrust of said input shank directly to the housing and the other transmits the thrust of the housing directly to said output shank.

3. A drill press attachment comprising a housing, an input shank extending from one side of said housing, said input shank being adapted to be mounted on the spindle of said press, an output shank extending from the 4 other side of said housing, said input and output shanks being axially aligned, speed change gearing within said housing operatively connecting said shanks, and a thrust bearing on each of said shanks, said thrust bearings being carried by said housing inwardly of said shanks and adapted to transmit thrust from said input shank to said output shank through said housing.

4. In a drill press attachment having a cylindrical body with an axial bore extending therethrough, and with at least one counterbore adjacent said axial bore and having its axis parallel thereto, the improvement therewith comprising a pair of thrust bearings mounted in 'the axial bore, a first shank extending outwardly from said body in one direction, and a second shank extending outwardly from said body in an opposite direction, each of said shanks being axially aligned and having their ends rotatably mounted on said thrust bearings, whereby thrust is transmitted from said first shank to one thrust bearing,

' and through said body to the other thrust bearing and the second shank.

5. In a drill press attachment according to claim 4: including means adapted to prevent rotation of said body when said attachment is mounted on a drill press.

6. In a drill press attachment according to claim 4: in which each of said shanks is rotatable, a pinion gear adjacent the end of each shank, and means adapted to fit the counterbore and operatively interconnect said pinion gears. I

7. In a drill press attachment according to claim 6: including a'cover for each side of said body, and each of said covers having an anti-friction bearing therein coaxial with the mentioned body bore, said shanks being freely rotatable within said anti-friction bearings.

References Cited in the file of this patent UNITED STATES PATENTS 1,104,736 Schneider July 21, 1914 1,444,343 Goodwin Feb. 6, 1923' 1,735,398 Doagland Nov. 12, 1929 2,428,049 Tate Sept. 30, 1947 

